Posts Made By: Shawn Hinzey

Welp, yes, I'm bringing this up again. Only because the winter season approaches, I'm breaking out my scope and my OM-1 and visited my local photolab. Come to find out they have the capability of outputting drum scans up to 500mb medium format files, pretty cool.
Anyways, I was wondering again about the actual benefits of CCD over film when it comes to resolution. Someone correct me if i'm wrong please, but the latest Canon 20D shoots a max resolution of about 3500x2300 (8.2MP), bit depth of 12 across the board, saves in RAW and JPG, and has a film plane of 22.5x15 mm. A cheap Epson photo scanner does about 4800x9600 dpi (with interpolation 12800 x 12800) has 48 bit color and 16 greyscale, can output in multiple high quality formats (JPG can cause noise and artifacts), as well as scanning 35mm and med. format which is innordinately larger. 200 bucks for scanner... 1800 bucks for 20D.

It seems to me the more I analyze the market that with every new digital camera there is also a marked increase in scanner technology (makes sense since they both largely use CCD). With the limitations of film basically limited to our ability to process the info. on it (i.e. scanning and/or interpolating it)can there ever really be a doubt as to which is the better medium?

Im really asking this because I'm thinking about purchasing a scanner and getting further into 35mm and was wondering if I should just bone up and drop some coin on an expensive CCD.

Is it possible to autoguide with the neximage planetary viewer? I'd assume it IS, especially with the reducer available from ATWB. I've got a CG5-GT I need to autoguide with, hopefully I can use this perhaps on an ST-80 with guidedog. Any thoughts?

I'm about to embark on an interesting idea I had for my C6-RGT. As of now, it actually doesnt have too much chromatic aberration, albeit it is still noticible. A good collimation definitely helps.
At any rate, per the definition of chromatic aberration basically the lens doesnt focus light near the blue wavelength (and some red) to the same point as other wavelengths, which is why u see blue edges.
NOW, this being the case... using RGB filters with achromats should not be too much of a big deal. Why?? After switching color filters you'll refocus each time. Even when using a stiletto u can easily get the same framing of your shot simply by using index marks on your camera. If you're worried about rack and pinion focuser image shift, just make a note of whether your focuser is in perfect alignment as you're slewing in or out (assuming you've collimated your focuser and taken note of whether u were slewing in or out at perfect collimation).

Assuming u pinpoint each color with a ronchi screen and take precautions with camera placement and image shift you should be able to get the clearest, brightest, most contrasty images in any scope of that comparable aperture save an APO. As well, using film with RGB cuts way down on reciprocity failure, meaning u can use higher grain films without too much consideration for this. Lastly, with drum scans or even quality home-scanning technology u'll still be ahead of the DSLR game when u go to post processing as good quality home-scanners are still way ahead of DSLR. Amd of your frames are not exactly the same of course u can align it post-processing digitally.

Note: one could conceive using this same technique photographing in the Sulfur, mercury, Ha, etc. wavelengths too.


So, given all the money u'll save using an achromat and a simple 35mm with a ronchi or varimagni it's way worth it. If you dont want to invest in a filter wheel u could always purchase the filters only and simply place them in the image plane. Since u'll have to reset your camera anyways this isnt a big deal.

Recently I was wondering if it would be possible to use a DSLR as an autoguider for long-exposure 35mm shots. My girlfriend has a Minolta Dimage 7, which actually has done pretty well in astrophotography, I was even able to find the T-adapter for it. Anyways, it has the ability to take video as well as stills and also has a video out.

My idea is to simply use its video out and its superior CCD (with longer, fully manual exposure times) connected to a PC w/guidedog. Assuming guide-dog will accept it as a video capture device, it should work.

Anyone ever tried anything like this?

Note: this camera has the ability to output video in NTSC or PAL. As well, it can adjust capture speed from 4fps up to 15. Shutter speed goes down to 4 seconds max.

For those of you who think u cant use NTSC or PAL to guide, all u need is a video grabber, that converts analog signals into digital. These cost 50 bucks.

Im in desperate need of an autoguider, but am torn which to use. I've decided not to fool around with webcams as I simply wont have the aperture to make up for the inability to image dim stars and I prefer not to tinker too much.

Anyways, I'm runnin a C6-RGT and came across these 2 systems. What's ur opinions? Basically they resell for the same prices now. I'm still debating whether or not I'm going to want to lug a laptop with me. More and more it seems like I should, even if I'm doing film photography. That being the case many will say to still use a webcam and save money.

Any opinions?

Welp, these 2 imagers are basically the same price. I currently am using an c6-RGT (achro.) with an OM-1 and need an autoguider/imager. Need input on the advantages and disadvantages of both, and opinions on which one to purchase in my situation. Bear in mind I will be needing to do RGB or Ha, OIII, etc. to eliminate chromatic aberration and will be needing guidance for my OM-1.

Assuming u could isolate color channels with the MX5c (which u can do with software OR filtering perhaps?) one could assume u can still alleviate the aberrations.

The 237 is more sensitive but will need a color wheel and wont be able to guide when I decide to image with it... or will it? 8)

So, opinions?

Welp, these 2 imagers are basically the same price. I currently am using an c6-RGT (achro.) with an OM-1 and need an autoguider/imager. Need input on the advantages and disadvantages of both, and opinions on which one to purchase in my situation. Bear in mind I will be needing to do RGB or Ha, OIII, etc. to eliminate chromatic aberration and will be needing guidance for my OM-1.

Assuming u could isolate color channels with the MX5c (which u can do with software OR filtering perhaps?) one could assume u can still alleviate the aberrations.

The 237 is more sensitive but will need a color wheel and wont be able to guide when I decide to image with it... or will it?

So, opinions?

I'm currently working on making my own motorized focus slide (will upload the steps/plans later). The idea is to basically be able to use many sized filters, but I'm leaning towards the 75mm Wratten type (unmounted square) because they will be able to be used in front of a camera lens as well as in the 2" image back on my scope, due to their size. Anyways, I was just wondering how good these are for RGB work??? It's either these or 55+mm mounted glass filters for this slide.

Thanks
Shawn

Well... I live is South Florida which actually has some of the best winter viewing there is because of the everglades and temperature. But, close to home is terrible of course. No matter WHAT I'll be transporting to a dark sky area out west in the swamps.

I have a large enough vehicle so I'm not worried about either scope. Setup time is better on the Dob of course, just heavier to carry.

On all other merits is where I get a little confused in choosing.

Thanks... looks as if a guidescope is still the way to go. Too bad it makes the whole setup really huge.